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Monday, March 31, 2014

The Soil Association[1]
was founded in 1946 and today is the main body for the certification of organic
farms in the UK. It’s website has a section on pesticides, which states the
following: “Around 31,000 tonnes of
chemicals are used in farming in the UK each year to kill weeds, insects and
other pests that attack crops. There is surprisingly little control over how
these chemicals are used in the non-organic sector and in what quantities or
combinations. What we do know is that 150 of the available 311 pesticides
commonly used have been identified as potentially causing cancer and many of us
would have been exposed to these pesticides before we were born”. It then
goes on to state: ”Even food that we
think is healthy, such as non-organic Cox's apples, can be sprayed 18 times.
The most dangerous chemicals used in farming, such as organophosphates, have
been linked with a range of problems including cancer, decreasing male
fertility, foetal abnormalities, chronic fatigue syndrome in children and
Parkinson's disease”. This linking of organic food with a reduced exposure
to so-called cancer-causing pesticides is a widely held belief among organic
food advocates.

That view within the organic
movement is unlikely to be changed by a recent study refuting this belief but
the majority of people who are made to worry about this alleged
pesticide-cancer link will take solace from its findings. The paper, published
in the British Journal of Cancer[2]
was based on data from The Million Women study, which was based on a million
women screened for breast cancer, followed these women over a 12 year period
with questionnaires on lifestyle completed at baseline and at years 3, 8 and
12. In the year 3 questionnaire, women were asked about their consumption of
organic food within categories, “never”, “sometimes”, “usually” or “always”. A
total of 751,975 provided data on their organic food intake in year 3. In this
particular study part of the study, women were excluded if they had changed
their diet in the previous 5 years because of an illness. That then left the
researchers with data on 623,080 women.

At the outset of the study,
30% of women reported never consuming organic food, 63% sometimes consumed
organic food and 7% reported always or usually eating organic food. During the
follow up period of almost 9 years, a total of 53,769 women were diagnosed with
some form of cancer. The authors looked at the relative risk of 16 cancers
across the frequency of use of organic food. They controlled for age, area of
residence, body mass index, smoking, physical activity, alcohol intake, age at
first birth, fibre intake and type of meat intake. Compared to women who never
consumed organic food, there was a 9% greater
incidence of cancer among women who usually or always consumed organic food. The
one exception was Non-Hodgkin Lymphoma (NHL) where those who usually or always
consumed organic food had a 21% lower risk of NHL than women who never consumed
organic food.

Already the organic movement
is claiming that the 21% reduction in NHL is proof that pesticides are a
causative factor in cancer. However, NHL in the UK accounts for just 4% of all
cancers. Thus there were 161,215 cases of cancer among UK women in 2011 of
which 155,358 or 96% of all cases did not involve NHL with cancer of the breast,
bowel, lung, uterus and ovaries accounting for 62% of all cancers[3].
No matter what way the organic advocates dredge the data, the simple fact
remains that the consumption of organic food had no overall protective effect
against cancer (indeed it was 9% higher in the organic food consumers).

Plants maintain a natural
defence system against pests and thus the overall load of exposure to natural
pesticide is enormous concerned to our exposure to pesticides used in
agriculture whether for commercial or organic agriculture. Data shows that
using the rodent carcinogenic model, of the plants natural pesticides, 55% were
positive carcinogens and 45% were not[4].
All available data show that about half of all naturally derived chemicals are positive
in the rat carcinogenic model. The figure for all synthetic chemicals is also
about 50%. Natural doesn’t equate with safety. Think of hemlock, magic
mushrooms, opium, caffeine and nicotine to name a few.

People make all sorts of
decisions about their lifestyle including diet. Some opt to be vegetarian. Some
prefer to eat organic food. Some choose food based on a perceived allergy. The
reasons are endless. So live and let live but please don’t preach about the
health virtues of organic food to consumers who are not so inclined for
whatever reason. Enjoy your food whatever your choice and let others enjoy
theirs. There are many great challenges facing us in terms of public health
nutrition. This paper, the first of its kind, has binned the claim of the
organic food movement that consuming conventionally farmed foods can lead to
exposure to cancer causing pesticides.

Friday, March 7, 2014

Understandably, there is a very strong focus in obesity
research on the diets of schoolchildren with many schools now attempting to
implement healthy eating policies.Equally, there has been considerable concern about the existence of food
retail outlets nearby to schools to which the schoolchildren have access. A
group at the University of Oxford has recently published a meta-analysis of all
relevant studies, which set out to examine the relationship between obesity
outcomes and the proximity of food retail outlets to schools[1].

The authors completed a search of 10 on-line library
databases and identified several thousand studies but, as ever, in
meta-analyses, many of the initial studies were rejected for a variety of
reasons leaving the authors with 30 full studies which met all of the a priori inclusion criteria. Each study had
to have defined exactly what was meant by the retail food environment and to
have measure quantitatively the relationship between food purchase patterns and
obesity-related outcomes. Most of the papers were published between 2011 and
2013 and most were cross-sectional with children ranging in age from five to
seventeen years. More than three quarters had sample sizes of over 1,000.

Of the 30 studies, the majority used a defined “buffer zone”
around the school but some used route maps between the pupil’s home and school.
GIS (Geographic Information Systems) software was the main source of
information on retail outlets either within the designated buffer zone or
school route. In general the buffer zone applied a distance of between 0.1 to
3.0 miles while the route approach generally used distances of 50 to 100 meters
from the road travelled to and from school. The main outcome studied was the
child’s BMI (kg/m2). The second most frequent measure of outcome was
food intake but this appeared generally to be related to a narrow range of
foods: fruit and vegetables, soda drinks or fast food. Some of course used
several measures and just three used the overall diet quality index of the schoolchildren
which would have included all sources of foods at all times of the day.

One study focused on fast food purchases and found a
statistically significant positive association between fast food purchasing and
the density of fast food outlets.Ten
studies examined the relationship between food outlets in general and the consumption of sugar sweetened
beverages and of fast food, including crisps, sweets, biscuits, fried food,
sugar sweetened beverages and fast foods. Within these 10 papers, a total of 54
associations were examined and only two of these showed a statistically
significant association. Four papers examined the association between fruit and
vegetable consumption and food retail outlets and within these a total of 32 associations
were examined. Only three showed statistically significant associations. Within
the 30 studies, only three had data on the overall quality of the pupil’s diet
and food retail outlet density. Two of these showed a significant association
between diet quality of food outlets. In one case, the data showed a
significantly higher diet quality index among pupils attending a school where
the nearest retail outlet was greater than 1 km away as compared to those where
the distance was less than 1km away. The second study found that the greater
the distance to the nearest grocers the better was the overall diet of the
pupils.

This is an important paper for several reasons. Firstly, it
is a very well conducted study published in a high impact journal. Secondly, it
highlights how the existence of evidence is happily ignored by those policy
makers who want to place restrictions on the availability of food outlets
within the vicinity of schools. Thirdly, it shows that the outcome variables
which are easy to measure such as fruit and vegetable intake, soda intake or
BMI yield fairly useless conclusions since they do not relate the one aspect of
the determinants of food choice (school associated food outlets) to the
totality of the effects of all food choice in terms of overall daily nutritional
quality. Once again, we see a majority of studies in what is a very important
area of public health nutrition, bedevilled by bad design. In the three studies,
which did look at the overall quality of the pupil’s diet and density of food
retail outlets two showed some significant associations. Now do two swallows
make a summer?. No, but they point the way forward for the conduct of scientifically
rigorous studies in this very important area of public health nutrition. To
discover that the proximity of food outlets influenced specific food intake is
of zero importance in public health nutrition. We need to know the full
accurate daily nutrient intakes and only then can we judge whether any aspect
of the obesigenic environment id truly influencing overall nutritional quality.

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"Ever seen a fat fox ~ Human obesity explored"

About Me

I graduated from University College Dublin in 1971 with an Masters in Agricultural Chemistry, took a PhD at Sydney University in 1976 and joined the University of Southampton Medical School as a lecturer in human nutrition in 1977. In 1984 I returned to Ireland to take up a post at the Department of Clinical Medicine Trinity College Dublin and was appointed as professor of human nutrition. In 2006 I left Trinity and moved to University College Dublin as Director of the UCD Institute of Food and Health. I am a former President of the Nutrition Society and I've served on several EU and UN committees on nutrition and Health. I have published over 350+ peer reviewed scientific papers in Public Health Nutrition and Molecular Nutrition and am principal investigator on several national and EU projects (www.ucd.ie/jingo; www.food4me.org). My popular books are "Something to chew on ~ challenging controversies in human nutrition" and "Ever seen a fat fox: human obesity explored"